A family of four in a Chicago suburb was shot dead by a man who later died in a fiery car crash with police in pursuit.

The suspect in the quadruple homicide is 32-year-old Nathaniel Huey Jr., of Streamwood, about an hour's drive from the Romeoville community where Alberto Rolon, 38, Zoraida Bartolomei, 32, and their two boys, ages 7 and 9, were murdered.

Family of four killed

The victims were found during a wellness check Sunday night after one of the victims did not show up for work.

Police believe the killings happened between 9 p.m. Saturday and 5 a.m. Sunday morning. They found the four victims and their three dogs with gunshot wounds.

The suspect's wife or fiancée was also killed in an apparent murder-suicide.

Huey Jr. eluded investigators for days before dying in a police chase near Tulsa, Oklahoma on Wednesday, with his partner Ermalinda Palomo, who was identified as a person of interest.

Police heard two gunshots after the suspect's car crashed and caught fire. Huey Jr. died at the scene and Palomo died later at the hospital from a gunshot to the head.

Suspect, partner dead

An attorney for Palomo's family said she was killed in a "murder-suicide" and that her family had reported her missing the night before. Palomo was a mother and grandmother.

"She communicated with members of her family, telling them such things as, 'I love you, take care of my grandbabies,'" said attorney John Paul Ivec.

Ivec insisted that Palomo, who lived with the suspect, had no role in the murders and was asleep at home when they happened.

"We know without a shadow of a doubt that at the time of the murders in Romeoville, Ermalinda was home sleeping. This has been confirmed by multiple family members," he said.

Criminal history

The exact relationship between Huey Jr., Palomo, and the four victims is not clear. The attorney for Palomo's family said she was engaged to Huey, but his Facebook says they were married.

Police say there is some kind of unspecified connection between Huey Jr. and the four victims and that a motive has been established, but they have not shared it yet.

Palomo's daughter told NBC that Huey Jr. was "very dangerous" and controlling.

"When I first met him, he wasn't too bad of a guy. A couple of months ago, something switched. He was shutting all of us out, including my mom, and now this," she said.

Huey Jr. had a criminal record that included arrests for battery and drunk driving - and he was under a court order banning him from owning firearms, CBS reported. He was also an estranged father of three.